title: Inflammation is related to coronary flow reserve detected by positron emission tomography in asymptomatic male twins.
abstract: OBJECTIVE
  This study sought to examine the relationship between inflammation and coronary microvascular function in asymptomatic individuals using positron emission tomography (PET) and assessment of coronary flow reserve (CFR).
  
  
  BACKGROUND
  Coronary microvascular dysfunction is an early precursor of coronary artery disease (CAD) thought to result from endothelial cell activation and inflammation, but data are limited.
  
  
  METHODS
  We examined 268 asymptomatic male monozygotic and dizygotic twins. Plasma biomarkers of inflammation and endothelial cell activation included C-reactive protein (CRP), interleukin (IL)-6, white blood cell count (WBC), vascular cell adhesion molecule (VCAM)-1, and intercellular adhesion molecule (ICAM)-1. Blood flow quantitation was obtained with [¹³N] ammonia PET at rest and after adenosine stress. CFR was measured as the ratio of maximum flow to baseline flow at rest; abnormal CFR was defined as a ratio < 2.5. A summed stress score for visible perfusion defects was calculated.
  
  
  RESULTS
  In within-pair analyses, all biomarkers, except VCAM-1, were higher in twins with lower CFR than their brothers with higher CFR (p < 0.05). This was observed in the entire sample, as well as within pairs discordant for a CFR of <2.5. Associations persisted after adjusting for summed stress score and CAD risk factors. In contrast no biomarker, except IL-6, was related to the summed stress score of visible defects.
  
  
  CONCLUSIONS
  Even in asymptomatic subjects, a decrease in coronary microvascular function is accompanied by a systemic inflammatory response, independent of CAD risk factors. Our results, using a controlled twin design, highlight the importance of coronary microvascular function in the early phases of CAD.
authors.affiliation: Department of Epidemiology, Emory University Rollins School of Public Health, Atlanta, Georgia, USA. viola.vaccarino@emory.edu
authors.forename: Viola
authors.initials: V
authors.lastname: Vaccarino
authors.forename: Durreshahwar
authors.initials: D
authors.lastname: Khan
authors.forename: John
authors.initials: J
authors.lastname: Votaw
authors.forename: Tracy
authors.initials: T
authors.lastname: Faber
authors.forename: Emir
authors.initials: E
authors.lastname: Veledar
authors.forename: Dean P
authors.initials: DP
authors.lastname: Jones
authors.forename: Jack
authors.initials: J
authors.lastname: Goldberg
authors.forename: Paolo
authors.initials: P
authors.lastname: Raggi
authors.forename: Arshed A
authors.initials: AA
authors.lastname: Quyyumi
authors.forename: J Douglas
authors.initials: JD
authors.lastname: Bremner
mesh_terms: D001167:Arteritis / Q000473:pathology / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology*; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000473:pathology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D012042:Registries; D014429:Twins, Dizygotic / Q000502:physiology*; D014430:Twins, Monozygotic / Q000502:physiology*